Safety latch and lock for door operators



Nov. 2l, 1933. A. H. SCHAFFERT Er A1.

SAFETY LATCH AND LOCK FOR DOOR OPERATORS 2 Sheets-Sheet l Filed Oct. 14, 1930 abtozmq Nov. 2l, 1933.

A. H. scHAFFERT Er A1.

SAFETY LATCH AND LOCK FOR DOOR OPERATORS Filed oct. '14, 195o 2 sheets-smet 2 anion/w44 Patented Nov. 21, 1933 VUNrrED STATES PATENT OFFICE SAFETY LATCH ANDr LOCK Fon Doon Y OPERATORS AdolfVr H. Schaflertand John B. Montgomery, Youngstown, Ohio, assgnors to Truscon Steel Company, Youngstown, Ohio, a corporation of Michigan "Application October 14, 1930. Serial No. 488,654

11 Claims.

' {Ihe' present invention'while' adapted for other yanalogous purposes, is primarilyfintended for large doorsused in buildings and warehouses.

VThese doors are ofthe lift type, ordinarily made *inv` sections and moved vertically to their openV positions. Beingof relatively great weight, shouldv Hthe elevating means, vas forexample a chain or other cable break, they are aptr to drop by gravity Vand cause serious injury.

f The object of the present-invention is to provide a. novel and simple form of mechanism for catchingand holding the door should the elevating means break or Abecome inactive.

*A'iurther and vimportant object is to providel Hsafetyapparatus of this character which will V'falso constitute a lock for preventing the doors beving improperly or-surreptitiously opened.

In the accompanying drawings:

f Figure 1 'is aninside elevation of a door structure showing the elevating means and the safety fimechanism. f 1 Y Figure 2 is aY detail sectional view through'one Vbcornerof a door section on anenlarged scale and *illustrating the'lsafety'latch in its inactive position;

Figure 3 is a sectional view on'the line 3-3 of Figure'2.

Figure 4 is a view similar to Figure 3, but illus-v trating thegsafetyl latch in its locking position to hold the door closed. Figure 5 is asectionalfviewon the line 5 5 of Figure 1.

- Figure l6 is'aview in elevation of a portion of 'Y 'the' guideways for the' door sections.

Figure '1f is a s'cuom vView on the une 7 7 of Figure 6. i

Inthe embodiment disclosed, a doorway 8 is provided with a frame including side members 9v fthatextend above the topof the doorway where they are connected to across beam structure 10.

The side members 9 include sets of guideways 11 preferably formed by abacking plate 12 Vwithouter vertical anglebars 13 and abutted central angle' bars 14 suitably secured', as by welding, to

the plate -12 and outstanding'therefrom to pro- Vvide the two guideways as shown lin Figure 7.

The backing wall 12 and the inner flanges of the angle bars 13 and 14 are provided at intervals withopenings15,-the'endwalls of which form stops or'shoulders. i

Slidablymounted in the guideways 11 are ver'- tically movable door sections 16 and 17 which may be of any desired character. The lower section 16 is shown aspanelled. The upper section`17 Vprovided with windows. Suitable means are pro-55 vided for elevating the two sections, preferably so that the lower section will move twice as fastas the upper section and the two sectionswill be located side by side when the door is elevated and, the doorway 8 opened. As illustrated a motor 18,9260

Ycontrolled by any suitable means. drives a cable 19 that passes around the sheaves 20V of drums 21 located at the upper corners of the door frame. Over these drums pass Vcables in vthe form of chains 22, each fixed at one end to the cross bearrf65 `10 as shown at 23 and having its other end supporting a counterweight 24. The cables 22 are looped between their ppoints of fastening 23 and the drum 21 and Vpassaround sheaves 25 at the upper corners ofthe upper section. These sheaves *70 are journaled on arms 26 of safety latches 27 pivoted to the uppercorners of the upper section 17. The lower section 16 of the door is lifted by chain cables 28 attached to the upstanding arms 29 of similar safety latches 30 pivoted to the7 5 upper corners of the lower section 16. It will be understood that these cables 28 pass over the drums 21. They are shown broken ou in Figure `1 in order to avoid confusion.

As the latches 27 and 30 are similar in all re-f 180 spects, except for the chain connections, the detail illustration in Figures 2-4 of one of the A latches for the lower door` section, it is believed,

will be suicient for all. The lower door section 16 is provided with a tubular frame 31 and at the^85 upper corner this frame is slotted in its Ytop as shown at 32, and in its side as illustrated at 33. The latch 30 is pivoted at 34 within the frame V31 and has its upstanding arm 29 projecting 443 on the frame 31. vPreferably theV frame on op- 100 posite sides of the slot 32 is reenforced as shown at 44.

The relation of the arms 29 and 35 of the latch 30 is such that when there is a strain on the liiting cable 28 the arm 29 will be vertical, the spring 10 will be under tension, and the locking hook and shoulder 36 will be within the slot 33, so that the hoolr` does not interfere with the raising and lowering of the door. If, however, the cable 28 should brealr when the door is elevated and the arm 29 is thus relieved of the lifting strain, the spring 40 will act to swing the latch so as to carry the arm 35 outwardly and it will enter one of the openings 15 of the guideway. The iiat shoulder will thereupon come to rest on the bottom wall of one of these openings, while the upper side of the arm will abut the outer reenforcement 4.4 as shown in dotted lines in Figure 2. The door therefore cannot drop, but will be caught and held, thereby avoiding any injury or catastrophe. In addition the operating mechanism is such that when the door is lowered to its closed position, the lifting chain 28 is allowed to slacken so that the latch will swing outwardly under the action of the spring ll0 and enter one of the openings. It does not now support the door, but as shown in Figure l if an Vendeavor is made to raise the door, for example, by prying under it, the book 37 will engage the top wall of the opening in which the end of the arm is located and prevent any material elevation of the door.

As already stated, the latches for the upper door section are constructed in precisely the same manner and operate in the same way, except that instead or a direct connection'between each cable and its latch, the cable passesaround the sheave 25 journaled on the arm 26.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description and it will be understood that Vvarious changes in the size, shape, proportion and minor Y details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

What we claim, is:

Vl. In combinationwitha doorway having a frame including vertical guideways at the sides of the doorway, of a `door slidable in the guideways, a stop associated with the guideways, a latch mounted on the door and adapted to engage the stop when the door is closed to lock the door against opening, a cable for elevating the door, said cable being connected to the latch and when under strain holding said latch away from the stop, and means for putting strain on the cable to elevate Vthe door, said means permitting the cable to slaclien when the door is closed and thereby allow the latch to engage the stop and lock the door against opening.

2. In combination with a doorway having a frame, and a door movable between an elevated position and a lowered closed position across the doorway, of a cable for elevating the door, and a combined safety latch for preventing the door from dropping if released from the cable and forv locking the door in its lowered closed position against elevation by means other than the cable.

3. In combination with a doorway having a frame and a door movable between an elevated position and a'lowered closed position across the doorway, of a cable for elevating the door, and

a combined safety latch for preventing the door from dropping if released from the cable and for locking the door in its closed position, said latch being held against its safety holding function by the cable and being released by the cable when the door is lowered to lock said door against elevation by means other than the cable.

e. In combination with a doorway including a frame, of guideways formed at the sides of the frame, vertically movable door-sections engaged in the guideways, stops formed in the guideways, latches pivoted to the upper corners of the door sections and movable into association with the stops, springs for thus moving the latches, cables connected to the door sections through the medium of the latches and when under strain holding kthe latches against engagement with the stops, andmeans for putting strain on the cables to elevate the door sections, said means giving slack to the cables when the door sections are closed to permit the latches to engage the stops and lock the door sections.

5. In combination with a door frame having a channeled guideway and openings formed in the bottom of the guideway, providing stops, of a door slidable in the channel of the guideway, a latch movably mounted on the door and movable into engagement with the stops, and a lifting cable for the door connected to the latch and when under strain holding the latch from engagement with the stops.

6. In combination with a door frame having sets of channeled side guideways and openings formed in the bottoms of the guideways, providing stops, door sections slidable in the channels of the respective sets of guideways, latches-.pivotally mounted on the upper corners of the door sections and having portions that swing into the openings, springs for swinging the latches to cause said entry, and lifting cables for the door sections connected to the latches `and when under strain holding them against movement by the springs.

7. In combination with a door frame having a guideway and stops formed therein, of a door having a tubular frame slidablein the guideway,

a latch pivoted within the tubular frame and having a portion movable beyond the same into engagement with the stops, and a lifting cable for the door connected to the latch and when under strain holding the latch fromY engagement with the stops.

8. In combination with a doorway including a channeled guideway having a bottom provided with openings, a door having a tubular frame portion slidably engaged in the guideway, a latch mounted in the tubular portion of the door and having a holding portion that is movable beyond the same into the openings, `and an elevating cable for the door engaged with the latch and when under strain, holding it out of said openings.

9. In combination with a doorway including a channeled guideway having a bottom provided with openings, a door having a tubular frame portion slidably engaged in the guideway, aV latch mounted in the tubular portion of the door and having a holding portion that is movable beyond the same into the openings, said latch also having an upstanding portion that projects out o1 and above the frame, and an elevating cable for the door engaged with the upstanding portion of the latch and-when under strain, holding it out of said openings. Y

10. In combination with a doorway and a door movable between an elevated and a lowered position across the doroway, means for elevating and lowering the door, a safety device controlled by the elevating means and operating when it fails to prevent the door dropping, and means with which the safety device engages when the door is lowered for holding the door against elevation by means other than said elevating means.

11. In combination with a doorway and a door movable between an elevated and Va lowered position across the doorway, means for elevating and lowering the door, a stop and locking means 

